Windowed door for self-cleaning oven



March 17, 1970 p. DE WEE$E ETAL 3,500,815

WINDOWED DOOR FOR SELF-CLEANING OVEN 3 Sheets-Sheet 1 Filed May 21, 1968S W? M. mwmm T E 4 VESN -J IDUMPV WHQM;

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WINDOWED DOOR FOR SELF-CLEANING OVEN 3 Sheets-Sheet 2 Filed May 21, 19682 ....m. E wwww w W WWW W 3 4 G I Y. 23

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WINDOWED DOOR FOR SELF-CLEANING OVEN Filed May 21, 1968 3 Sheets-Sheet 5E1. HER H. ME/S/NGER FRANK D. Pens/04s 6JIW9%;'MQILJ7 s a i. 1 E J o: n@u. NM: 92 N: m E i V H w-wlll|l= I n gfifigw a! m D. HE... W Q I W m2 ug: M "a" MIMI, r 1 m n H n n m OM u n u u u h u m fi of u n n n u n T Lrdiw m m m m M a n n ".1 fig United States Patent 3,500,815 WINDOWEDDOOR FOR SELF-CLEANING OVEN Raymond P. DeWeese, Elmer H. Meisiuger, andFrank D. Prindle, Kankakee, Ill., assignors to Geo. D. RoperCorporation, Kankakee, 11]., a corporation of Delaware Filed May 21,1968, Ser. No. 733,217

Int. Cl. F24c 15/04 US. Cl. 126--20l) 12 Claims ABSTRACT OF THEDISCLOSURE A door for a self-cleaning oven formed of spaced panelshaving registering window openings, enclosed front and back by sheets ofglass with a shutter normally occupying a pocket below window levelbetween adjacent panels with linkage for manually elevating the shutterinto radiation-obstructing position in the window. Ports are providedfor flow of cooling air behind the front panel and an interlock isprovided for preventing start of the selfcleaning cycle unless theshutter is in place.

It is an object of the invention to provide a windowed door for aself-cleaning oven which is highly efiicient minimizing loss of heatfrom the oven cavity either by Way of conduction, convection orradiation. It is a related object to provide a door for a self-cleaningoven which permits tempenatures on the order of 900 F. to be achievedinside the oven while maintaining the front of the oven at a safe lowtemperature level. It is another object of the invention to provide, ina door of the present type, a shutter which not only obstructs andreflects radiation from inside the oven but which is internallyinsulated so as to prevent any appreciable conduction of heat from theinside surface of the shutter to the outside.

It is another object of the invention to provide a windowed door for anoven in which the radiation-obstructing shutter has a linkage forraising and lowering which is extremely compact, occupying a narrowspace at the lower edge of the door but which nevertheless has a largestroke with a toggle arranged to support the shutter in its elevatedposition, permitting use of a window of maximum slze.

In one of the aspects of the invention it is an object to provide aneffective interlock to prevent the start of a self-cleaning cycle unlessand until the shutter is in its fully upraised position; once in thisposition, with the range in its locked cleaning mode, the shutterposition cannot be altered. This is accomplished in the present instanceby an obstructing member which consists of a single pivoted lever and ashutter raising handle located on the inside of the closed and lockeddoor.

It is yet another object to provide a windowed door for a self-cleaningoven which is efficient, yet inherently simple to make and assemble.

Other objects and advantages of the invention will become apparent uponreading the attached detailed description and upon reference to thedrawings in which:

FIGURE 1 is a perspective view of a range having a door utilizing thepresent invention;

FIG. 2 is a sectional view looking along the line 22 in FIG. 3;

FIG. 3 is a sectional view looking along the line 3--3 in FIG. 2;

FIG. 4 is a fragmentary section looking along the line 44 in FIG. 3;

FIG. 5 is a diagram showing the shutter elevating linkage in theupraised, toggled position and with the inter-' lock engaged;

FIG. 6 is a fragmentary elevation looking along the line 66 in FIG. 3and showing the interlock in obstructing position; and

FIG. 7 is a fragmentary section looking along the line 7-7 in FIG. 3showing the interlock in non-obstructing position and the lock engaged.

While the invention has been described in connection with a preferredembodiment, it will be understood that we do not intend to be limited tothe particular embodiment shown but we intend to cover, on the contrary,the various alternative and equivalent constructions included within thespirit and scope of the appended claims.

Turning now to FIGURE 1, there is shown a range 10 of the free-standingtype having a door 11 constructed in accordance with the presentinvention which encloses an oven cavity '12 surrounded by a facing orjamb surface 13. The oven has heating means (not shown) which areemployed for baking and for raising the temperature of the oven to aself-cleaning level, on the order of 750- 900 F. or above, withappropriate setting of the controls 15 and timer 16. To complete thestructure, heating elements 17 are provided on the cooking top under thecontrol of the usual control knobs 18.

Reference may be made, if desired, to prior patents and publicationsdisclosing self-cleaning ovens as, for example, Hurko Patent 3,121,158.It will suffice to say that incident to initiating a self-cleaning cyclethe oven door 11 is locked closed by a hook type locking member 20 whichengages a member 21 through an access slot 22 (FIG. 7), the member 20being projectable from the jam'b surface upon throwing of a locking arm23. In ovens of the self-cleaning type the lock member is held in itslocking position until the temperature within the oven cavity is againreduced to a safe level.

In accordance with the present invention a door is provided having awindow in the upper portion thereof and which is distinguished by aliner panel and intermediate panel spaced from one another to form astorage pocket for an insulated shutter with means for transporting theshutter upwardly into radiation-obstructing position. Spaced outwardlyfrom the intermediate panel to define a space for conducting cooling airis a front panel, and spaced rearwardly from the liner, and insulatedtherefrom, its a door plug, the front panel and door plug havingregistering openings each covered by a sheet of heatresistant glass.Thus, turning particularly to FIG. 2, the door 11 has a liner panel 30providing a window opening 31 of generally rectangular shape. The linerpanel is bordered by a flat land surface 32 upon which is seated agasket 33 to seal the joint with the oven jamb surface 13 about the topand sides of the door. The gasket 33 is preferably interrupted at 34along the bottom edge of the door to permit a small amount of air toenter during the self-cleaning cycle. The edges of the panel 30 are bentforwardly as shown at 35 to provide a peripheral flange for mating witha similar flange on a front panel as will be discussed.

Spaced forwardly from the liner panel 30 and mounted on pillars 36,which are four in number, is an intermediate panel 40 providing a windowopening 41 and having a forward y offset portion 42 for defining a space43 behind it, which is filled with insulation. The intermediate panel isflanged at the bottom and top as indicated at 44, 45. A retainer panel46 serves to enclose the space 43 to confine the insulation and to serveas a mounting plate for shutter-elevating linkage to be described. Thestructure described thus far defines a pocket 47 which accommodates aninsulated shutter 50' slightly larger than the window opening. Theshutter has spaced front and back walls 51, 52 and a periphery 53defining a central space 54 which is preferably packed with insulation.The walls 51, 52 are both made of heat-resistant sheet material, as forexample, steel, and at least the rear wall is provided with aheat-reflecting surface which may, for example, be aluminized. The frontwall may be decoratively finished as desired.

To conduct the shutter upwardly and downwardly, track structure 60 isprovided having vertical track members 61, 62 of channel-shaped crosssection bridged by a channel shaped top member 63. The track memberssurround the window opening and serve as a rigid spacing member betweenthe panels 30, 40 on each side. The track structure is held in place byan integral flange 64 clamped under an auxiliary clamping member 65. Forthe purpose of facilitating movement of the shutter and to take up theexcess space within the channels, the shutter is provided withanti-friction shoes in the form of graphite pads 66.

In carrying out the present invention a front panel 70 is providedhaving a window opening 71 alined with the window openings 31, 41 andcovered by a sheet of heatresistant glass 72, the glass being held inplace by suitable clamps 73. The front panel is bent rearwardly aboutits edges to provide a rearwardly extending flange as indicated at 75which overlies the flanges 35 on the liner panel and which is secured tothe latter by means of recessed screws 76. To provide rigid seating ofthe front panel, with respect to the intermediate panel, whilepermitting passage of air through the interspace and behind the glasswindow 72, a spacer frame 80 is provided formed of metal of channelcross section which is shaped to surround and generally conform to theshape of the window opening. The spacer frame 80 preferably has aforwardly extending flange 81 which defines a receptacle for seating thesheet of glass 72. Moreover, the spacer frame 80, and particularly thelower and upper runs thereof indicated at 82, 83, has a set ofperforations 84 occupying approximately fifty percent of the area forconducting cooling air along the inner surface of the glass. Foradmitting cooling air along the lower edge of the outer panel 70', suchpanel is provided with a set of slot-like apertures 85. A set ofapertures 86 formed in the upper run of flange 75 provides venting atthe top of the door structure. Cooling air thus flows along the path ofthe arrows 87, entering at the bottom and exiting at the top. Since thecooling air is heated by the time that it reaches the top of the doorready for discharge, means are provided for preventing direct thermalcontact between the heated air and the upper portion of the outer panel.This is accomplished in the present instance by a body of insulation 88held in place by an insulation retainer 89.

Mounted at the rear of the door is a door plug 90 of rectangular panshape having a window opening 91 which registers with the windowopenings in the panels previously described and which is covered by asheet of heat-resistant glass 92. The plug 90 is of drawn constructionhaving a sidewall 93 terminating in a lip 94 of smaller profile than theliner panel and which serves to clampingly hold in place the strip ofgasketing material 33 previously mentioned. The space 95 between theoven plug and the liner panel is preferably filled with insulation.

Interposed between the door plug 90 and the liner panel 30 is a secondspacer frame 100, similar to the spacer frame 80 and having a rearwardlyextending flange 101 which serves as a receptacle for the glass window92, the spacer frame and window being clamped securely to the door plugby means of clamps 103. A resilient gasket 105 interposed between theglass window 92 and the door plug seals the glass and prevents passageof the products of decomposition into the door structure during aself-cleaning cycle.

In carrying out the present invention a first set of lnternal pillarsare provided for connecting the front panel subassembly to the liner pnel so th t the spacer frame on the front panel assembly engages theintermediate panel about the periphery of the window and in juxtaposedrelation the guide tracks. Moreover, a second set of pillars areprovided for connecting the door plug assembly to the liner panel sothat the spacer frame which forms a part of the door plug assembly bearsagainst the liner panel in the region around the window and, again,alined with the guide tracks so that there is bottomed seating of all ofthe superimposed members upon one another about the periphery of thewindow thereby to rigidify the door structure and to enable easyassembly. Thus in assembling the present door, the liner panel andintermediate panel are first secured together with the channel shapedtrack assembly between them and with the shutter and control mechanism,to be described, mounted between them. For securing the front panel tothe liner panel, pillars are provided which are preferably spot weldedat 111 to the front panel and which form a seat for the forwardlyfacing, inside surface of the liner panel. A screw 113 penetrating aregistering opening in the liner panel screws into a suitably tappedhole in the surface 112. A total of six of such pillars 110 may be used.Similar, but shorter, pillars are used to secure the door plug to theliner panel. Such pillars indicated at 120, and four in number, are spotwelded to the liner panel as indicated at 121 to provide a supportingsurface 122. A suitable machine screw penetrating a registering openingin the door plug engages the pillar 120, drawing the door plug up tightso that the spacer frame 100 bears against the rear surface of the linerpanel and so that the gasketing material 33 is simultaneously clampedinto position against the land surface on the liner panel. Not only dothe pillars 110, 120 insure easy assembly to form a rigid and securelyclamped door unit, but they permit easy disassembly whenever it may benecessary to have access to the interior of the door, for example, whenit becomes necessary to clean the inside surfaces of the glass windows72, 92.

It is one of the features of the present construction that a manuallyoperated linkage is provided for transporting the shutter 50 upwardlyinto its obstructing position between the windows. Such linkage, shownin FIGS. 3 and 5, is preferably of the lazy tongs type actuated by apair of toggle links which in turn are operated by a manual operatingarm occupying a shallow recess in the surface of the door plug. Thus,the lazy tongs linkage includes a first link having a pivot 131 which isrelatively stationary and having a second pivot 132 which engages aslotted member 133 at the lower edge of the shutter. In crossed relationis a second link 134 which is pivoted at 135 to the lower edge of theshutter, and which has a second pivot 136 which engages a slottedstationary member 137. To insure equalized movement of the two links,they are connected, at their centers, by a pivot 138. To elevate thepoint of pivoting 138, a toggle linkage 140 is provided having a firsttoggle member 141 and a second toggle member 142 pivoted together at acommon pivot 143. Toggle member 141 is secured, at its lower end, to ashaft 144 which is journaled in suitable openings 145, 146 in the panelmembers 46, 90, respectively. A manual operating arm 147 secured to theshaft 144 by a screw 148 occupies a shallow recess 149 formed in thedoor plug.

For the purpose of defining a relative position of the two toggle links141, 142, which is just beyond the vertical dead center position, a stop150 in the form of a tang 151 on one of them which bottoms in a groove152 in the other. Thus, in operation, throwing the arm 147 from itsnormal position to its shutter-raising position causes rotation of theshaft 144 in the counterclockwise direction producing extension of thetwo toggle members 141, 142 and elevation of the central pivot 138. Thiscauses the two links 131, 134 to expand with scissor-like action raisingthe upper points of pivoting, 132, 135 of the links o that the shutteroccupies a radiation-obstruc ing post tion between the windows 72, 92.Since the toggle links rotate slightly overcenter, before bottoming ofthe stops 151, 152 occurs, the shutter is stably held in its upraisedposition without any special latching means and without resorting tofriction. The shutter is lowered with equal ease simply by reversing thedirection of movement of the actuating arm 147. When the shutter is inits lowered position, the upper edge indicated at 53 in FIG. 2 spans thepocket and lies flush with respect to the spacer frame 82 and windowedge 31 thereby to provide a smooth finished appearance when viewedthrough the front window In accordance with one of the aspects of thepresent invention, a mechanical interlock is provided at the upper edgeof the door for normally covering the access slot 22 to prevent entry ofthe hook or locking member 20. This is accomplished in the presentinstance by an obstructing member 160 having a slot obstructing portion161 at one end an engageable portion 162. at the other, the member beingpivoted centrally at 163. A spring 164 normally biases the obstructingmember in the direction of the arrow 165 so that the slot is obstructedas shown in the fragmentary view, FIG. 6. Thus in the event that someoneattempts to operate the lever 21 (FIG. 1) by swinging it into itslocking position, the projection of the locking member or hook 20,reacting with the obstructing member causes the door 11 to be pressedoutwardly thus signalling to the user that the shutter has not beenraised as required. The door is then opened about its lower hinge (notshown but having a center 166), and the shutter actuating arm is swungto its alternate position, expanding the linkage, raising the shutterand causing the obstructing member 160 to be rotated about the centralpivot 163 so that the end 161 thereof moves out of register with respectto the slot 22. Subsequent movement of the locking lever 21 will thencause the hook 20 to move through the slot for hooking onto the hookengaging member 21 which forms a part of the door structure.

It is found that a door constructed as described above not only inhibitsloss of heat by radiation, conduction or convection, but presents anexterior panel surface which remains at a safety low temperature inspite of the fact that the oven cavity may be raised to a temperature of800 F. or more for a period which is as variable but which may be longas several hours. It is to be particularly noted that the shutter, inaddition to providing a radiation refiecting surface 52, which insuresproper cleaning of the interior window surface 92, is filled withinsulation to inhibit thermal conduction which may have the effect ofraising the temperature of the outer surface 51 of the shutter beyondsafe lirnts. The rigid insulated shutter which fits tightly within thetracks 60 has the further advantage, in the event of breakage of theinner glass, of inhibiting passage of outside air into the oven cavityto form a possibly explosive mixture. It will be appreciated that sincethe inner surface 52 of the shutter is subjected to a high level ofthermal radiation, notwithstanding use of the aluminized surface, and isless than one hundred percent efficient, a portion of such radiation isabsorbed to raise the temperature of the inner surface of the shutter.However, due to the presence of the insulation 54, the outer surface 51is kept below a temperature at which any harmful degree of radiation canoccur. Thus ones hand may be placed directly in front of the windowduring the self-cleaning cycle without feeling more than a gentlewarmth, and there is no risk of overheating and possibly damaging apiece of kitchen furniture which may be inadvertently placed in front ofthe oven during the time that self-cleaning is going on. Moreover, thesurface 51 of the shutter may be decoratively finished to provide anattractive appearance when elevated into view without risk that thedecoration will become scorched by overheating.

The arrangement is highly compact since the lazy tongs linkage occupiesonly a very small space at the lower edge of the shutter which, in turn,permits, a maximum window size; yet the linkage provides a long strokenecessary to move the shutter to its fully upraised position. Positivemechanical interlocking is provided by placing the obstructing memberdirectly in the path of movement of the upper edge of the shutter. Uponengagement, the obstructing member is rotated against the force of itsbiasing spring 164 as the toggle linkage 141, 142 approaches and as itmoves beyond its dead center position with a high degree of mechanicaladvantage. The fact that the shutter remains upraised when the actuatingarm 147 is released is proof positive that the linkage has been movedbeyond center and that the mechanical interlock has been fully actuated.

What is claimed is:

1. In a door for enclosing a self-cleaning oven, the combinationcomprising a liner panel and an intermediate panel having registeringwindow openings in the upper half thereof, the members being spacedapart to define a pocket below the window level, a front panel spacedforwardly of the intermediate panel, a door plug spaced rearwardly ofthe liner panel, said front panel and door plug each having registeringwindow openings, sheets of high temperature glass covering the windowopenings in the front panel and door plug, a rectangularly shapedshutter in said pocket of a dimension larger than the window openings,said shutter being formed of spaced layers of heat resistant materialdefining a central space substantially filled with thermal insulation,tracks for guiding the shutter upwardly, and manually operated means forelevating the shutter along the tracks into a position fully obstructingthe window openings'thereby to obstruct direct radiation of heat fromthe oven.

2. The combination as claimed in claim 1 in which the inner layer ofheat resistant material has a heat reflecting surface.

3. The combination as claimed in claim 1 in which the door plug is panshaped having a lip of smaller outer dimension than the door liner todefine a peripheral land surface for seating of the door against theoven structure, a layer of gasketing material held captive between thelip on the door plug and the door liner in a position overlaying theland surface.

4. The combination as claimed in claim 1 in which the elevating meansincludes a lazy tongs linkage arranged below the shutter and coupled toit with a manual operator for extending the lazy tongs linkage therebyto move the shutter into its obstructing position.

5. The combination as claimed in claim 4 in which the manual operatingmeans is in the form of a pair of toggled links having an accessiblemanual operating handle and so arranged that the toggle links movebeyond their dead center position as the shutter reaches the upper limitof its movement, thereby to sustain the shutter in upraised position.

6. The combination as claimed in claim 1 in which the front panel isprovided with openings along its lower and upper edges to permit the airwhich enters at the bottom to flow between the sheet of glass mounted inthe front panel and the shutter when the shutter is in the raisedposition.

7. The combination as claimed in claim 1 in which the track is in theform of a spacer frame of channel cross section sandwiched between thedoor liner panel and the intermediate panel in a position juxtaposed tothe other two spacer frames, and fastener means for maintaining theassembly made up of the spacer frames and panels solidly bottomed uponone another to rigidify the construction.

8. In a door for enclosing a self-cleaning oven having a manuallyoperated locking member projectable from the oven jamb for entering intothe oven door structure for engaging and locking the same, thecombination comprising a door liner panel presenting a fiat marginalsurface for flatly engaging the oven door jamb, an intermediate panel,said panels having registering window openings near the top portionthereof and spaced apart to define a pocket below the window level, afront panel spaced forwardly of the intermediate panel and a door plugspaced rearwardly of the liner panel and both supporting glass windowsalined with the window openings in the liner panel and intermediatepanel, a pair of vertical track members leading from the pocket to thespace between the glass windows, a shutter mounted in the track membersand normally occupying a position recessed in the pocket, a lockengageable member behind the liner panel and adjacent the periphery andhaving an access slot for entry of the projectable locking member on thejamb of the oven, a movable obstructing member mounted adjacent the slotand biased into normal obstructing position to prevent entry of theprojectable locking member, manual means for elevating the shutter alongsaid tracks into a position between the glass windows to prevent directradiation of heat therethrough, and means for coupling the obstructingmember to the shutter so arranged that when the shutter moves into itsupper position the obstructing member is moved against the force of biasto a position clear of said slot thereby to permit entry of theprojectable locking member for locking of the door during aself-cleaning cycle.

9. The combination as claimed in claim 8 in which the movableobstructing member is in the form of a centrally pivoted lever havingone end normally positioned obstructingly adjacent the slot and theother end arranged in the path of movement of the shutter to effectrocking of the lever during the last portion of movement of the shutter.

10. In a door enclosing a heated cavity the combination comprising anouter door panel having a window opening, an inner door panel having aregistering window opening, a first sheet of heat resisting glass, asecond sheet of heat resisting glass, a void between the glass sheetsand a heat insulating shutter formed of spaced layers of heat resistantmaterial defining a central space substantially filled with thermalinsulation, such shutter being movable between the glass sheets so as toobstruct direct radiation of heat from the heated cavity.

11. In a door for enclosing a self-cleaning oven, the combinationcomprising a liner panel and an intermediate panel having registeringwindow openings near the top, a guide frame including vertical inwardlyfacing track members along the lateral edges of the window opening andextending downwardly to define a pocket below window level, aninsulating shutter having its lateral edges slidably fitted in saidtrack members, a front panel spaced forwardly of the intermediate paneland having a registering window opening covered by a first sheet ofheatresistant glass, a first spacer frame behind the first sheet ofglass including clamping means for clamping the spacer frame tothe'front panel to provide a front subassembly, a door plug having aregistering window opening covered by a second sheet of glass, meansincluding a second spacer frame having clamps for clamping the secondspacer frame and sheet of glass to the door plug to provide a door plugsubassembly, mating flanges at the periphery of the liner panel andfront panel, first mounting means including pillars between the frontpanel and the liner panel for clamping the front panel assembly so thatthe first spacer frame bears against the intermediate panel in theregion of the tracks, and second mounting means including pillars forclamping the door plug subassembly with respect to the door liner panelso that the second spacer frame bears against the door liner panel inthe region of the tracks to provide a solid stack of superimposedstructural elements about the window all the way from the front panel tothe door plug thereby to rigidify the central portion of the door, andmanual means for elevating the shutter along the tracks intoradiationobstructing position between the glass windows.

12. In a door for enclosing a self-cleaning oven, the combinationcomprising a liner panel and an intermediate panel having registeringwindow openings in the upper half thereof, the members being spacedapart to define a pocket below the window level, a front panel spacedforwardly of the intermediate panel, a door plug spaced rearwardly ofthe liner panel, said front panel and door plug each having registeringwindow openings, sheets of high temperature glass covering the windowopenings in the front panel and door plug, a rectangularly shaped heatinsulating shutter in said pockets of a dimension larger than the windowopenings, said shutter having inner and outer walls uniformly spacedfrom one another and with the space between the walls being occupied bythermal insulating material to inhibit transfer of conducted heat fromthe inner wall to the outer wall through the thickness dimension, tracksfor guiding the shutter upwardly, and manually operated means forelevating the shutter along the tracks into a position fully obstructingthe window openings thereby to obstruct direct radiation of heat fromthe oven, said front panel having openings along its lower and upperedges to permit air entering at the bottom to flow between the sheet ofglass mounted in the front panel and the outer wall of the shutter whenthe shutter is in the raised position.

References Cited UNITED STATES PATENTS KENNETH W. SPRAGUE, PrimaryExaminer

